(a) Scope and purpose. The objective of this section is to aid in preventing the introduction and accumulation of fats, oils, and greases into the municipal wastewater system which will or tend to cause or contribute to sanitary sewer blockages and obstructions. Food service establishments and other industrial or commercial establishments generating wastewater containing fats, oils or greases are subject to this section. This section regulates such users by requiring that grease interceptors and other approved strategies be installed, implemented, and maintained in accordance with the provisions hereof.
(b) Definitions. See section 32-69.
(c) Grease interceptors shall be installed and maintained at the user's expense, when a user operates a food service establishment. Grease interceptors may be required in non-cooking or cold dairy and frozen foodstuffs establishments and other industrial or commercial establishments when the establishment generates wastewater containing fat or grease and the ORC determines an interceptor is necessary to prevent contribution or accumulation of grease to the sanitary sewer collection and treatment system. Upon notification by the ORC or designee that the user is subject to the terms of an enforcement action, said user shall not allow wastewater discharge concentration from subject grease interceptor to exceed an establishment action level of 100 milligrams per liter, expressed as hexane extractable material. All grease interceptors shall be of a type, design, and capital approved by the ORC and shall be readily and easily accessible for maintenance, and repair, including cleaning and for town inspection. All grease interceptors shall be serviced and emptied of accumulated waste content as required in order to maintain minimum design capability or effective volume of the grease interceptor, but not less often than every 60 days or as permitted in a valid program modification. Users who are required to pass wastewater through a grease interceptor shall:
(1) Provide a minimum hydraulic retention time of 24 minutes at actual peak flow between the influent and effluent baffles, with 25 percent of the total volume of the grease interceptor being allowed for any food-derived solids to settle or accumulate and floatable grease derived material to rise and accumulate, identified hereafter as a solids blanket and grease cap respectively.
(2) Remove any accumulated grease cap and solids blanket as required, but at intervals of no longer than 60 days at the user's expense, or in accordance with the valid program modification or other ORC's requirements. Grease interceptors shall be kept free of inorganic solid materials, such as grit, rocks, gravel, sand, eating utensils, cigarettes, shells, towels, rags, etc., which could settle into this solids blanket and thereby reduce the effective volume of the grease interceptor.
(d) If the user performs onsite grease interceptor treatment pursuant to a modification granted below, the user shall:
(1) Prior to commencement of onsite treatment, obtain written approval by and from the ORC of all processes utilized in said onsite treatment.
(2) Meet the criteria contained in subsection (d)(3)c of this section if any pumped wastes or other materials removed from the grease interceptor are treated in any fashion onsite and reintroduced back into the grease interceptor as an activity of and after such onsite treatment.
(3) Attain and adhere to the criteria listed:
a. After 30 minutes of setting time, not more than 3.0 mg/L of settleable solids, as measured in a one-liter Imhoff cone shall be allowed.
b. Within and not more than 24 hours after onsite grease interceptor servicing, not more the two inches of settable solids and/or grease shall be allowed to have accumulated therein as a result of said operations.
c. Service vehicles and equipment used in onsite grease interceptor servicing shall be registered with the public works and utilities department, and as required by the state division of waste management.
d. When servicing grease interceptors, service vehicles and equipment shall have onboard, at all times, a certificate of approval for the operations and methods used, issued by the ORC.
e. Any tanks, tankage, or vessel associated with a modification shall be empty upon arrival at the initial FSE user site for which this modification is intended to be applied. Operate and maintain the grease interceptor to achieve and consistently maintain any applicable grease action level. Consistent shall mean any wastewater sample taken from such grease interceptor must meet the terms of numerical limit attainment described in subsection (d)(3)a of this section. If a user documents that conditions exist (space constraints) on their establishment site that limit the ability to locate a grease interceptor on the exterior of the establishment, the user may request an interior location for the interceptor. Such request shall contain the following information:
1. Location of town sewer main and easement in relation to available exterior space outside building.
2. Existing plumbing layout at or in a site.
3. A statement of understanding, signed by the user or authorized agent, acknowledging and accepting conditions the ORC may place on permitting an identified interior location. Conditions may include requirements to use alternative mechanisms, devices, procedures, or operations relative to an interior location.
4. Such other information as may be required by the ORC.
(e) The use of biological or other additives as a grease degradation or conditioning agent is permissible only upon prior written approval of the ORC. Any user using biological or other additives shall maintain the trap or interceptor in such a manner that attainment of any grease wastewater, action level, solids blanket or grease cap criteria, goal or directive, as measured from the grease interceptor outlet of interior, is consistently achieved.
(f) The use of automatic grease removal systems is permissible only upon prior written approval of the ORC, the lead plumbing inspector of the county, and the Rutherford Polk McDowell District Health Department or the U.S. Department of Agriculture. Any user using a grease interceptor located in the interior of the site shall be subject to any operational requirements set forth by the state division of waste management. Any user using equipment shall operate the system in such a manner that attainment of the grease wastewater discharge limit as measured from the unit's outlet, is consistently achieved as required by the ORC.
(g) The ORC may make determinations of grease interceptor adequacy need, design, appropriateness, application, location, modification, and conditional usage based on review of all relevant information regarding grease interceptor performance, facility site and building plan review by all regulatory reviewing agencies may require repairs to, or modification or replacement of grease interceptors. The user shall maintain a written record of grease interceptor maintenance for three years. All such records will be available for inspection by the town at all times. These records shall include:
(1) FSE name and physical location.
(2) Date of grease interceptor service
(3) Time of grease interceptor service.
(4) Name of grease interceptor service company.
(5) Name and signature of grease interceptor service company agent performing said service.
(6) Established service frequency and type of service: full pump-out, partial pump-out, onsite treatment (type of nature of operations.)
(7) Number and size of each grease interceptor serviced at FSE location.
(8) Approximated amount, per best professional judgment of contract service provider, of grease and solids removed from each grease interceptor.
(9) Total volume of waste removed from each grease interceptor.
(10) Destination of removed wastes, food solids, and wastewater disposal.
(11) Signature and date of FSE personnel confirming service completion.
(12) Such other information as required by ORC.
No non-grease-laden sources are allowed to be connected to sewer lines intended for grease interceptor service.
(h) Access manholes shall have an installed diameter of 24 inches, a maximum weight of 50 pounds, and shall be provided over each chamber, interior baffle wall, and each sanitary tee. The access penetrations, commonly referred to as risers into the grease interceptor shall also be, at a minimum, 24 inches in diameter. The access manholes shall extend at least to finished grade and be designed and maintained to prevent water inflow or infiltration. The manholes shall also have readily removable covers to facilitate inspection, grease removal, and wastewater sampling activities.
(i) A user may request a modification to the following requirements of this article. Such request for a modification shall be in writing and shall provide the information set forth in subsection (j) of this section.
(j) The user's grease interceptor pumping frequency. The ORC may modify the 60 days grease interceptor pump out frequency when the user provides data, and performance criteria relative to the overall effectiveness of a proposed alternate and such can be substantiated by the ORC. Proposed alternatives may include grease interceptor pumping or maintenance matters, bioremediation as a complement to grease interceptor maintenance, grease interceptor selection and sizing criteria, onsite grease interceptor maintenance, and specialized ware washing procedures.
(k) Grease interceptor maintenance and service procedures. The ORC may modify the method or procedure utilized service a grease interceptor when the user provides data, and performance criteria relative to the overall effectiveness of a proposed alternate method or procedure and such can be substantiated by the ORC. If a modification to maintenance and service procedures is permitted it shall be a conditional discharged permit approval.
(l) Any modification must be approved by the ORC in written form before implementation by the user or the user's designated service provider.
(Code 1989, § 51.18)